Their street still unplowed, Matt and Kim Lanier and their daughter Jenna, 16 months, head out on foot on the Boston Post Road in Milford, Conn., on Sunday.

Grabbing shovels large and small, residents and emergency workers across the Northeast struggled to dig out on Sunday after a gigantic midwinter storm left much of the region buried under drifting snow. City streets resembled ski slopes or mountain passes, with cars and even some houses obscured by a thick blanket of white.

More than 3 feet of snow fell in parts of Connecticut, and more than 2 feet accumulated on Long Island and in Massachusetts, where the storm caused coastal flooding that forced evacuations.

The National Weather Service said it had reports out of New Haven County, Conn., of 36.2 inches of snow in Oxford and 38 inches in Milford. Commack, on Long Island, got 29.1 inches, and MacArthur Airport in Islip with 27.5 inches. In Boston, the official accumulation was 24.9 inches, the fifth highest in city history.

Armies of snow plows and workers with shovels were making slow progress, and anxiety was growing among those unable to escape their homes and neighborhoods.

“I hope I’m plowed out by Monday night,” said Emanuel Machado, 47, an architectural designer in Westport, Conn. “By that time, I’ll be running out of groceries.”

The storm, spawned by the collision of two weather systems, affected more than 40 million people. So far, only a handful of people have died, including several elderly people who died of heart attacks while shoveling snow. Several people, including a boy in Boston, have died from carbon monoxide poisoning, while seeking refuge from the cold in cars.

By Sunday morning, more than 300,000 customers remained without power, down from 650,000, mostly in southeastern Massachusetts and on Cape Cod, in Rhode Island and on the eastern Connecticut shore. NStar, which provides much of Massachusetts with electricity and natural gas, said it was still too dangerous to send in crews to many areas. Flooding during the storm also caused extensive damage to the electric infrastructure in Massachusetts.

Getting rid of all the snow is now the most pressing concern.

President Barack Obama declared a state of emergency in Connecticut on Sunday, ordering federal aid to supplement local emergency response efforts.

Calling the storm “historic,” Gov. Dannel P. Malloy, praised the president’s decision, and pressed residents to stay out of the way of emergency crews until the snow was cleared.

“While the ban on travel has been lifted, we are continuing to urge residents to stay off the roads, if at all possible,” Malloy said in a statement. “This is particularly true for tractor-trailers. Every time someone gets stuck, it is preventing plows from doing their jobs.”

For some, moving at all has proved nearly impossible. In Old Lyme, Conn., Beth Hamilton and her husband, Matthew Barrett, still had no power on Sunday and were cooking and warming their home with a wood-burning stove. Hacking through all the snow has been difficult.

“We really don’t know what’s going on, but there has not been a single snow plow through here yet,” said Hamilton, a composition teacher, who answered her cellphone sounding winded and exasperated. “We’re shoveling, just nonstop shoveling,” she said.

Coming less than four months after Hurricane Sandy walloped the New York and New Jersey area, the winter storm boldly confirmed the merciless side of nature, and weather-anxious residents took it very seriously. People crowded supermarkets and supply stores to stock up as the storm bore down. Long lines formed at gas stations.

Though New York City was spared the worst of the damage, out on Long Island the situation was grimmer. On Sunday, Gov. Andrew M. Cuomo of New York said officials scrambled to send workers and equipment to Suffolk County, where hundreds of motorists were trapped on roadways during the storm because of quickly falling snow.

In what he described as one of the largest emergency mobilizations for a snowstorm in state history, Cuomo said more than 600 pieces of snow removal equipment and about 1,000 extra workers had been sent to dig out the county.

“The state will continue to do everything possible to augment existing recovery work, and will ensure that residents of Suffolk County can go back to life as normal as quickly as possible,” Cuomo said in a statement Sunday morning.

A large section of the Long Island Expressway, which runs through Suffolk County, was closed on Sunday to clear snow.

Michael Krieger, 47, traveled from Raleigh, N.C., to Suffolk County with a snow removal crew and spent Saturday and early Sunday clearing parking lots. He said Saturday’s sun had melted some of the snow and created a crust of ice above wet, heavy snow.

“It’s a lot harder to dig through this stuff,” said Krieger, who was to shift to the Boston area later on Sunday. “It’s a tedious deal. Arduous.”

Off the roads, transportation woes had eased somewhat by Sunday. Airlines have begun to restore service after canceling more than 5,000 flights because of the storm. Logan International Airport in Boston and the three major airports in the New York City area have all resumed operations.

Amtrak announced that it had resumed limited service between New York and Boston. Metro North service remained suspended between Samford and New Haven in Connecticut, but was otherwise running on a normal Sunday schedule. The Metropolitan Transit Authority also said that most service on the Long Island Railroad had been restored.

For some, the best remedy has been to slowdown, grab a sled and enjoy the strange and often beautiful new landscapes.

Scrambling over snowy hills and frozen thoroughfares in Cambridge, Mass., Georgina C. Perry needed extra time to make it to church on Sunday morning. But it was something of a blessing, she said.

“I imagined I was at the Alps, without the altitude,” she said. “I’m so, so pleased that I was part of this phenomenal natural event.”